Derive the backscattering coefficients of particles from in-situ measurements

Abstract

The ocean color satellite sensors measure the water-leaving radiance from ocean, which is used to deduce the global chlorophyll-a concentration distribution and other information. The water-leaving radiance is mainly caused by the backscatter of particles in the water. Spectral backscattering coefficients of particles play an important role in determining the remote sensing reflectance and a model is developed to study the spectral characteristics of the particle backscattering coefficients. The backscattering model of particles is established based on the measured data at two wavelengths of 470nm and 700nm and the backscattering coefficients of phytoplankton are also deduced from the total particles. The parameter n in the model is deduced from chlorophyll-a instead of using a constant value and the backscattering coefficient of particles at 700nm is retrieved from chlorophyll-a using a power function. To deduce the backscattering model of phytoplankton, the ratio of phytoplankton absorption to the total absorption of particles is used to separate the phytoplankton part from total backscattering values. The backscattering model of phytoplankton is established with a high correlation coefficient of 0.80 and the parameter values of the model are very close to those of Sathyendranath. The range of phytoplankton backscattering coefficients is from 0.0018 to 0.016m-1, almost half of that scattered by total particles. The backscattering properties of phytoplankton also agree with the normalized diffuse attenuation coefficients of seawater, which can be used in the bio-optical models in the coastal ocean. © (2008) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.